Electric arc welders that generate more than 100 amps of welding current typically require a fuel-powered engine to drive an electric generator which in turn generates the required current for a welding operation. The size of the engine and electric generator is dictated by the maximum welding output rating of the welder. For instance, a welder that is rated to generate a 300-amp, 33.3 volt arc requires 10 kilowatts of power to generate such an arc. The engine in such a welder must have a large enough horse power to drive an electric generator to generate at least 10 kilowatts of power so as to supply the maximum welding output rating of the welder at any given time. The cost associated with large engines and associated electric generators significantly increases when large welding currents are required. The size of the engine and electric generator and the size of the fuel tank required to power the engine results in a significant increase in the size and the weight of the engine welder, which also results in increased cost and increased inconvenience in moving and storage of the welder. The energy inefficiencies that are associated with engine welders are also significant, especially in light of increased energy costs. The duty cycle during a normal stick welding operation is typically between 20-40% of the time. As a result, 60-80% of the time, the power being generated by the engine driven electric generator is not used, thus is wasted.
In view of the current state of engine driven welders, there is a need for a lower cost and/or more energy efficient arc welder.